Method for Manufacturing a Module for Treating a Fluid

ABSTRACT

A module enabling individual adaptation by the user to the respective task in the treatment of fluids using housings and connections of existing filtration devices without any modification is described. The module comprises one or more cells stacked one on top of the other, each of these having at least one opening, the opening of the cell or the similar openings of the cells together forming at least one channel for feeding or discharging the fluid to be treated. Each cell has two flat, porous components delimiting an inner space and designed for passage of the fluid therethrough, the inner space or spaces being connected to the channel. The inner space of the cell or cells contains at least partially a treatment material for the fluid. The method for manufacturing such a module makes provision for a treatment material to be introduced with a carrier fluid into the cells through the channel provided for feeding the fluid.

This application is a continuation of International Application No.PCT/EP01/15195, filed Dec. 21, 2001, which is incorporated herein byreference in its entirety and for all purposes.

BACKGROUND OF THE INVENTION

The invention relates to a module for treating fluids with one or morecells stacked one on top of the other, each of these having at least oneopening, the opening of the cell or the similar openings of the cellstogether forming at least one channel for feeding the fluid to betreated, each cell having two flat, porous components delimiting aninner space, and the inner space or spaces being connected to thechannel. The invention also relates to a method for manufacturing suchmodules in accordance with the preamble of patent claim 12.

In filtration technology it is known to use filter candles with fillingswhich either form a precoat or are introduced in the dry state.

Such a filter device is known from DE 39 43 249 A1. This comprises aperforated core pipe, a perforated support casing, a completely closedtop closure cap carrying a guide element, and a bottom closure caphaving a central opening with a connection piece connected thereto. Thecavity formed between the core pipe, the support casing and the twoclosure caps is filled with bulk material consisting of reclaimablefiltration-active substances. The fluid to be filtered flows in radialdirection from the outside to the inside, and the filtrate is dischargedthrough the core pipe.

The disadvantage of this device is that it must be filled by the candlemanufacturer because the filled cavity is closed when the top closurecap is fitted. This means that the user must specify the type of fillingmaterial when ordering the filter candle. A further disadvantage is thatthe filling may settle when transported or stored for a longer time,thereby creating a free space through which the unfiltered fluid flowsthrough the candle.

DE 38 02 816 A1 describes a candle-shaped filter element, the outercircumferential wall of which is in the form of a porous support layerfor a filter cake. This filter cake is formed by precoating filtermaterial, for example, kieselguhr or fiber mixtures and adsorbents suchas activated carbon, silicic acid material and the like. When the filtercake is worn out, it is washed away by back flushing and replaced by anew precoated filter cake, and the precoated filter material of theremoved filter cake has to be recovered in a complicated way outside thefilter housing. It is, at any rate, necessary to precoat a new filtercake prior to continuing with the filtering operation. This filteringdevice has the disadvantage that only precoatable materials can be used.

DE 32 04 022 C2 describes a filter cartridge which is supposed to havegreater stability and improved efficiency. The cartridge has a coaxialstructure and is filled with filtration-active material through whichthe fluid flows essentially in axial direction owing to the walls beingformed by permeable and impermeable sections.

In filtration technology it is also known to use filter modules having anumber of filter cells which are stacked one on top of the other andeach have a central opening.

These filter modules differ in their design and operation.

A variant of these known filter modules has a central support pipe onwhich the prefabricated filter cells are arranged in a row between twoadapters attached at the ends. When assembling the filter module, thefilter cells are pressed together and held so as to be sealed from oneanother. Such a filter module is described, for example, in DE 37 41 552A1, where prefabricated filter cells are used.

Another variant of known filter modules dispenses with a support pipe.On their inner circumference the filter cells are provided at thecentral opening with retaining and connecting rings which are weldedtogether when stacking the filter cells on one another so as to join thefilter module and make it into a solid unit. Other embodiments providespacer and/or drainage elements which are arranged as disc-shapedelements between the filter layers and/or filter cells and make itpossible for these to be mechanically joined to one another.

In spite of different designs of the filter modules, the filter cellshave in common that the filter sheets are made of flat materials suchas, for example, filter cardboards, papers, tiles or fabrics.

So-called filter layers are widely used as filter sheets. A depth-filtermaterial comprising organic and/or inorganic fibrous and/or granularsubstances is to be understood by this term.

As a rule, cellulose and/or plastic fibers which may havefiltration-active substances such as, for example, kieselguhr orpearlites embedded therein are used as base material for these filterlayers. Kieselguhr and pearlites serve to enlarge the inner surface andtherefore increase the capacity to absorb the turbid matter.

The filter layers are used in fields ranging from clarification andtreatment of liquids throughout the entire beverage industry to thepharmaceutical and chemical industries. Filter layers do not only have ascreening effect whereby coarse particles are retained on the surface ofthe filter layer, but also, in particular, a depth effect for fineparticles which are retained in the void spaces within the depth-filtermaterial. Depending on the type of materials used, these filter layersmay, for example, also have an adsorbing effect or interact with theunfiltered fluid in another way which goes beyond the purely mechanicalfiltration effect. Moreover, the surface may be subsequently treated forcertain applications so as to prevent detachment of fibrous particles inthe dry and damp states.

To date, the purpose of the filtration has always determined thecomposition of the filter layers. This means that production of thefilter layers has always had to be preceded by definition of theirsubsequent range of application.

Since any conversion of the method of producing the filter layersentails problems and minimum quantities always have to be produced,small batches of specially adapted filter layers are relativelyexpensive.

The filter modules may be operated in two ways.

A filter module in which filter cells and support bodies are alternatelystacked on one another along a central pipe is known from EP 0 233 999A2. The filter cells also contain supporting structures for supportingthe filter material of the filter cells. The unfiltered fluid is fed tothe filter cells from the exterior, and the filtrate is dischargedthrough the interior of the filter cells and through the central pipe.Herein it is disadvantageous that, on the one hand, the support bodiesprevent uniform feed of the unfiltered fluid to the filter cells, and,on the other hand, the filter substances accumulate on the supportbodies between the filter cells throughout the entire interior of themodule filter.

To remedy these deficiencies it was proposed in DE 198 57 751.6-27 thatthe unfiltered fluid be fed through the central channel of the filtercells. These filter cells to which the fluid is fed from the interiorrequire corresponding support bodies between the filter cells to preventinflation of the filter layers during filtration. Filter modulesdesigned and operated in this way are also referred to as inversemodules.

The object of the invention is to create a module which the user canindividually adapt to the respective task in the treatment of fluidsusing housings and connections of existing filtration devices withoutany modification.

The object is accomplished by the interior of the cell or cells at leastpartially containing treatment material.

SUMMARY OF THE INVENTION

Within the scope of the invention, cells are to be understood as alltypes of filter cells, but these cells are not only used for filtrationbecause the treatment material introduced into the cells is not limitedto filtration-active materials but may also include other substancessuch as, for example, extractors.

The application of the module is thereby extended beyond filtration.

The advantage of the module according to the invention is that the rangeof application of the module does not have to be specified for itsmanufacture because this is only determined when the treatment materialis selected. This opens up the possibility of making the cells fromneutral porous components which do not contain any special additives. Itis therefore adequate, for example, to produce filter layers from theknown base materials, i.e., essentially from cellulose and/or plasticfibers. The cost of manufacturing the filter modules is therebyconsiderably reduced because only a few types of porous components suchas, for example, filter layers have to be produced in large batches, andthe purpose for which they are to be used is only specified later by thechoice of treatment material. However, the invention is not limited tothese so-called neutral components.

It is thereby made possible for the user himself to fill the module onsite, which is particularly advantageous when the materials are toxicand expensive.

In addition, he can introduce his own material about which he may haveknow-how of his own. Sensitive materials whose efficacy may suffer fromtransportation from the module manufacturer to the user or fromintermediate storage can be introduced on site shortly before operationof the module. The service life of a filling is then no longer aproblem.

Since the further development of the modules according to the inventionrelates to the filling of the cells in association with the porouscomponents, there is no need to alter the dimensions of the module, andexisting filter housings and connections may therefore be used.

The treatment material may be powdery, granular, fibrous and/orgel-like.

Apart from filter layers, membranes such as plastic or metal membranes,woven or non-woven fabrics may also be used as flat, porous components.

Filtration-active materials are preferably used as treatment materials.These include all known substances such as, for example, pearlites,kieselguhrs, fibrous materials, but also adsorbents such as activatedcarbon, PVPP, PVPP-iodine substances.

It has been found that the efficacy of, for example, activated carbon orPVPP is significantly greater than with filter layers in which thesematerials have been embedded in the filter layer during the manufacturebecause the active surfaces are impaired by the incorporation in thefilter layer. With the module according to the invention lessfiltration-active material is thus required for the same performance andeffect. This is particularly advantageous when expensive materials areused.

Sensitive materials may now also be used as adsorbents. It is thuspossible to introduce into the filter module adsorbents which in theproduction of filter layers would become inactive as a result of theproduction process, for the production of the filter layers is based onan aqueous mash which has to be dried in a furnace. In this productionprocess water-sensitive or heat-sensitive adsorbents would lose theireffectiveness during the production. It is thus possible to open upcompletely new fields of use for such a module.

Extractors such as, for example, materials of plant origin, whichrelease active substances and thereby impart certain ingredients orproperties to the fluid to be treated may also be used as treatmentmaterials. It is also possible to combine filtration with meteredaddition of active substances. Preset porous components may also beused, and the metered addition may be carried out via the treatmentmaterial.

The interior preferably contains dry treatment material, which has theadvantage that, in particular, materials which are sensitive to moisturemay be used.

The treatment material is preferably applied to the inner side of theporous components. The filling level for the respective application canbe determined by way of the amount of material, taking into account theexisting cell volumes.

In accordance with a further embodiment the interior of the cells may beprovided with a material in which the treatment material is embedded orto which the treatment material adheres. A non-woven fabric or a porousfilm with adherent surfaces is preferably used. It is thus possible touniformly distribute, in particular, adsorbents in the cell, whereby theefficacy of the materials is increased even further. Shouldtransportation of the filled filter modules prove necessary, there is norisk of the treatment material thereby becoming unevenly distributed inthe interior of the cells.

The powdery or granular treatment materials preferably have a grain sizeof from 0.01 mm to 10 mm. Surprisingly, it has been found that filterlayers have an optimum structure for such powdery or granular materials,which does not lead to blockage. A significantly longer service life isthereby achieved.

The method for manufacturing such a module provides for the cells to beprefabricated and then assembled into a module or for the cells to beformed with assembly of the module, and for a treatment material to beintroduced with a carrier fluid into the cells through the channelprovided for feeding the fluid.

This takes advantage of the fact that the interior of the cells isaccessible from the outside through the channel without any conversionmeasures having to be taken for the filling.

Gases or fluids may be used as carrier fluid, and this complies with thetype of treatment material. If the treatment materials are sensitive tomoisture, a gas will be chosen, and vice versa.

Air is preferably used as carrier gas, but other carrier gases such as,for example, inert gases may also be used if the treatment materials areparticularly sensitive and interact with oxygen.

The treatment material is preferably introduced into the cell or cellsby a pressure gradient, for example, with a pressurized gas pulse. Ithas been found that use of a pressurized gas pulse results in a uniformdistribution of the treatment materials in all the cells.

Other preferred methods of introducing the treatment material are of amechanical nature such as, for example, shaking, vibrations or stuffing,and these methods may also be performed with fluid support.

1-16. (canceled)
 17. A module for treating fluid comprising: at leasttwo cells stacked on top of each other, the cells each having at leastone opening, the opening of each cell together forming at least onechannel for feeding or discharging the fluid to be treated, the channelbeing suitable for introducing a treatment material for the fluid intothe cells; the cells each having two sheet-like porous componentsdelimiting an inner space designed for passage of the fluidtherethrough, the inner space of each cell being connected to thechannel, wherein the inner space of each cell includes the treatmentmaterial for the fluid, wherein the treatment material comprises afiltration-active material selected from the group consisting ofpearlite, kieselguhr, activated carbon, PVPP, and PVPP-iodinesubstances.
 18. The module of claim 17, wherein the sheet-like porouscomponents comprise membranes.
 19. The module of claim 17, wherein thesheet-like porous components comprise fabrics.
 20. The module of claim19, comprising a woven fabrics or non-woven fabrics.
 21. The module ofclaim 17, wherein the sheet-like porous components comprise non-wovenfabrics.
 22. The module of claim 17 wherein the treatment material isuniformly distributed in the cell(s).
 23. The module of claim 17,wherein the treatment material includes activated carbon.
 24. The moduleof claim 17, wherein the treatment material includes PVPP.
 25. A methodfor treating fluid comprising: obtaining a module comprising one or morecells stacked one on top of the other, each cell having at least oneopening, the opening of the cell, or the openings of the cells together,forming at least one channel for feeding or discharging the fluid to betreated, the channel being suitable for introducing a treatment materialfor the fluid into the cell(s); each cell having two sheet-like, porouscomponents delimiting an inner space and designed for passage of thefluid therethrough, the inner space being connected to the channel,wherein the inner space of each cell at least partially contains thetreatment material for the fluid, wherein the treatment materialcomprises a filtration-active material selected from the groupconsisting of pearlite, kieselguhr, activated carbon, PVPP, andPVPP-iodine substances; and, treating the fluid by passing the fluidthrough the module and through the inner space of the cell(s) and thetreatment material.
 26. A module for treating fluids comprising one ormore cells stacked one on top of the other, each cell having at leastone opening, the opening of the cell, or the openings of the cellstogether, forming at least one channel for feeding or discharging thefluid to be treated, the channel being suitable for introducing atreatment material for the fluid into the cell(s); each cell having twosheet-like, porous components delimiting an inner space and designed forpassage of the fluid therethrough, the inner space being connected tothe channel, wherein the inner space of each cell at least partiallycontains the treatment material for the fluid, wherein the treatmentmaterial comprises a filtration-active material selected from the groupconsisting of pearlite, kieselguhr, activated carbon, PVPP, andPVPP-iodine substances.
 27. The module in accordance with claim 26,wherein the treatment material is dry.
 28. The module in accordance withclaim 26, wherein the treatment material is powdery, granular, fibrousand/or gel-like.
 29. The module in accordance with claim 26, wherein thesheet-like porous components consist of filter layers.
 30. The module inaccordance with claim 26, wherein the sheet-like porous componentsconsist of membranes or fabrics.
 31. The module in accordance with claim26, wherein the treatment material is applied to an inner side of theporous components.
 32. The module in accordance with claim 26, wherein amaterial having the treatment material embedded therein or the treatmentmaterial adhered thereto is arranged in the inner space of the cell orcells.
 33. The module in accordance with claim 26, wherein the treatmentmaterial has a grain size of from 0.01 mm to 10 mm.
 34. The module ofclaim 26, wherein the sheet-like porous components comprise non-wovenfabrics
 35. The module of claim 26 wherein the treatment material isuniformly distributed in the cell(s).
 36. The module of claim 26,wherein the treatment material includes activated carbon.
 37. The moduleof claim 26, wherein the treatment material includes PVPP.